Catheters of the kind referred to are particularly useful for the administration of medicaments, more particularly for the continuous administration of anesthesia within the epidural or intra-pleural (interpleural) spaces. In each application, the space involved is relatively long and narrow and is relatively inaccessible except in a direction which is at an angle relative to the long axis of the space. In each instance, nerves and relatively delicate body tissues are involved which are subject to trauma, producing paresthesia and in some cases considerable discomfort and permanent injury due to disturbance of the relatively delicate tissue bordering the space. In extreme cases, puncture, irritation or erosion of the tissue can result.
In the use of intra-vascular catheters, relatively short, soft distal tips for catheters for venous and arterial use have recently come into use as a means of avoiding vessel puncture and the dislodgment of plaque with the vessel. In these applications, substantially all of the catheter dwelling within the vessel must be relatively stiff due to the need to guide and turn the catheter tip within the vessel. Because of this limitation, the soft tip employed on an intra-vascular catheter has at most been about one to one and one half centimeters in length. Catheters of this type have not been recognized or considered to be adaptable for use within the epidural or intrapleural spaces because the relativelY stiff material comprising the major part of the catheter may damage the delicate tissues within the space. Further, the restlessness of patients to whom anesthesia is administered by intra-pleural and epidural techniques increases the risk that the soft tip will become separated from the body of the catheter, particularly since the catheter may reside within the space over a period of many days or even weeks.